It is known that synthetic materials can be protected against microbial influences by incorporating antimicrobially active substances in these materials. In particular, it is known to incorporate phenoxyarsines, for example 10,10'-oxybis-phenoxyarsine, as an antimicrobial agent to protect these synthetic materials. This is generally carried Out by treating the plasticizer used in the manufacture of these synthetic materials, for example in the manufacture of vinyl resins such as polyvinyl chloride, with a solution of the phenoxyarsine. Various solvents for the phenoxyarsine have been proposed for this purpose. For example, phenols and aliphatic alcohols such as nonylphenol, as well as certain phosphites and phosphonates such as tris(dipropyleneglycyl)phosphite are disclosed in U.S. Pat. No. 3,288,674. In various respects these solvents have disadvantages which are to some extent considerable, namely:
low dissolving capacity at room temperature, PA1 high viscosity and difficulties associated therewith during the processing, PA1 troublesome odors, PA1 low boiling points, PA1 unsatisfactory miscibility with the plasticizers usually used in the plastics industry, and PA1 unfavorable toxicological properties, PA1 esters of polybasic acids (such as phthalic acid, adipic acid, trimellitic acid, sebacic acid) with monovalent alcohols, such as ethylhexyl alcohol, isodecyl alcohol, isotridecyl alcohol, having molecular weights of about 250 to about 500; PA1 polyesters of glycols, such as 1,2-propylene glycol, neopentyl glycol, with dibasic acids, such as adipic acid, sebacic acid having molecular weights of about 600 to about 1200; PA1 epoxidated vegetable oils, such as soya epoxide, castor oil epoxide; PA1 phosphoric acid esters, such as tricresyl phosphate, tri-2-ethylhexyl phosphate.
It has been found that it is possible to overcome the above-noted disadvantages by using certain organic solvents in combination with phenoxyarsine antimicrobial agents.